Auto coasting device



May 18, 1937. YJ. H. HUNT 2,080,484

AUTO COASTING DEVICE May 18, 1937.

J. H. HUN-rv AUTO COASTING DEVICE Filed May 25, 1951 s sheets-sheet 2 alito/:muli

May 1s, 1937. J H HUNT 2,080,484

lAUTO CQASITING DEVICE Filed May 25, 1931 5 Sheets-Sheet 5 gru/vanto@ Patented May 18, 1937 vAUTO CO'ASTING" DEVICE .John H. Hunt, Detroit, Mich., assignor, by mesne assignments, to`.General -Motors Corporation, Detroit, Mich., a corporation of Delaware Application May 25, 1931, Serial No. 539,773

9 Claims.

'This invention relates to motor vehicles. More .particularly it relates to control mechanism `for lmotor vehicles wherein power-operated means is usedto release the clutch.

aThe primary object is to improve the operation of such a power-operated clutch releasing ydevice. 4Aifurther and morespecific object is'to improve the action of clutch reengagement.

Other objects'and advantages will be vunder- -stood from the following specification.

`The invention will be described with reference .to'the accompanying drawings which showseveral illustrative embodiments.

. yIn the drawings- Fig. l is a view of an engine of a motor vehicle, .the lnovel .details associated therewith being .shown partly infsection.

Fig. 2 is a similar View of a modified form.

Fig. V3 is a view in section of a stillfurther modified embodiment.

Figffl is a vertical section of a power take-off device used with the several embodiments.

Fig. 5 is a View in longitudinal section in detail.

It is already well-known to operate the-engine clutch by power derived from some moving part D.fof the vehicle, compressed air, vacuum, circulating fluids or mechanical connections properly arranged having been used. These power Adelvicesfor clutch operation have-sometimes been @controlled by levers'or pedals having no `other i function. They lhave also been controlled by .interlinking with other controls on the carfsuch .fas'lthe gear shift leveror the accelerator pedal.

In'the latter case clutch engagement and disengagement may occur automatically at the same "o time the` gear shift lever or the accelerator pedal .is movedvv by the driver. Where the power-device --is operated automatically, clutch reengagement mayoccur `when there is -a'large diie'rence' in ,v --speed between the engine'lywheel and the clutch plates and engagement under such circumstances cancause undersirable'accelerations or decelerations of the vehicle. Thus the clutch power-operating device can be so connected that --.the -clutch is disengaged when the accelerator :is in its retracted position. If the drivercloses vthe throttle at high speed, thev engine soon slows fdown to the idling speed. If the accelerator is then pushed down to speed up the vehicle the 50 lclutch may reengage before the engine speed has V.increased again to rcar speed. The-engagement causes the engine to act momentarily asa brake which is` contrary to the desire of the operator who hasfdepressed the accelerator to cause the engine to r'accelerate' '-the vehicle.

The present invention provides means to'prevent clutch reengagement when the engine-speed is less than the clutch shaft speed, preventing the engine from acting as a'brake except asdesired by the operator. The means for controlling l5 clutch engagement: v-involves devices for creating a fluid pressure whenever the clutchshaft and engine shaft rotate at different speeds, the arrangement being such that the liuid pressure with respect to some reference pressure which maybe the pressure ofthe atmosphere,'is higher than the reference pressure when the clutch'shaft is turning faster than'the flywheel, and the fluid pressure is less than the reference pressure when the engine speed is greater than the clutchshaft speed.

Fig. l shows .one form which the invention may take.

Referring'to Fig. l, numeral 1 represents the engine of a motor vehicle. The engine is shown as provided with a carburetor 9 andl an induction pipe |I communicating with an intake vmanifold I3.

At l5 is a lever pivoted to the induction pipe,.the lever operating to'rotate a throttle valve within the induction pipe. spring |1 functions to hold the throttle valve in .a normally closed or engine idling position.

The

The position of the engine inits relation to the car is made clear by Fig. 1 which shows theY dash.|9, the toe board at 2|, and the floor board yat 23. The gear shift lever 25 operates as usualto shift gears shown in part by numeral v21 located in transmission housing 29. Pivoted to the toe board 2| is an accelerator pedal 3| which is actuated to its' release position by a spring.33. A tie-rod connects the pedal 3| to the throttle lever l5. At 3l is the conventional clutch pedal pivoted at 39. the clutch 40 which is shown in Fig. 3.

This pedal operates to release This When the operator'allows'the accelerator pedal to swing up under the influence .of spring 33,

'heV not only cuts oi the flow of explosive mixture but incidentally theretovhe renders active the clutch-releasing power device. -41 is a lpower cylinderwhaving'a cover -49 with an air opening A diaphragm 53 visclamped between the1 Y initial position. This connection between rod 51 and lever 59 permits the operation of the clutch by the pedal 31 without producing any movement o-f the elements concerned with the power operation of the clutch.

The movement of the diaphragm to the left is produced by a pressure differential on the two sides of the diaphragm. Pressure on the right side is always atmospheric, owing to the opening 5|. Provision is made to reduce the pressure on the left side of the diaphragm. A conduit is connected to the manifold I3 and to one end .of a valve member 91. The other end of the valve member has slidable therein a piston 69. To this piston is connected a rod 1| terminating in a valve 13 having opposite seats 15 and 11. A spring 19 tends to move the valve 13 to a position away from its seat 11. A pipe 8| connects the chamber in the power cylinder at the left of the Vdiaphragm to the region of the valve member adjacent the valve and between the seats, so that the space in the power cylinder to the left of the diaphragm may be put into communication with the suction pipe 65 when the valve 13 is moved from its sea-t 11. When the valve 13 is on its seat 11, the pipe 3| connecting the power unit with the valve member "61 cooperates with a pipe 83, and communication is affordedwith a control member 85 having an atmospheric opening 81.

A connection is provided between lever l5 and the piston 69 whereby the depression of the accelerator pedal 3| 4may not only rock lever |5 but also may move the valve 13 to its seat 11 to the end that the left side of the power unit may bevented through passages 8|, 61, 83, and 81. With the parts in this position the clutch will be engaged by the springs usually provided for the purpose. a a

Since there must be provided a further throttle opening movement after the valve 13 is seated, the following structure is provided. A rod 89 is pivoted to the piston |59 and secured as by threading to the end of a spring housing 9|. Slidable in the other end of the housing 9| is a head 93 on a rod 95 which is pivoted to an extension arm 91 of lever |5. A springr99 within the cylinder 9| yieldingly permits movement of the throttle lever I5 after the valve 13 is seated as will be obvious.

While the accelerator pedal is in the dotted line position, the valve 13 will be drawn from its seat 11 and seated at 15 so that the engine suction is operable to pull the diaphragm 53 and release the clutch. The parts are so arranged that the rst increment of movement of 'the pedal 3| downward from its dotted line position will move the valve 13 to its seat 11 without opening the throttle to any considerableextent, not enough to very greatly increase the rate .of rotation of the engine shaft. This iirst increment of movement serves to vent the power cylinder and permit the clutch to engage.- Thereafter and upon further movement of accelerator 3|, relative movement occurs bel to the air.

tween head 93 and cylinder 9| and the throttle continues to open.

If the operator now wishes to make a gear change or for any other reason wishes to release the clutch, as for coasting, he may remove his 5 foot fromrthe pedal 3| and the valve 13 shifts from seat 11 to seat 15 and the `engine suction causes the clutch to be released. It may be that the operator will wish to use his lengine for a brake, as on a steep hill. In that event he will 10 relieve the pressure on the pedal 3| to an extent sufficient to partly cut oif the supply of fuel, but not quite enough to reduce the engine to the idling speed it assumes when his foot is removed from the accelerator. 'Ihis partial movement 15, will be insufficient to move 13 from its seat 11 and the clutch will remain engaged so that the engine may be used as a brake. With complete removal of the foot the enginey assumes idling speed andv the clutch is released.

With a construction as abovev described, the operation may be somewhat unsatisfactory in one respect. If the operator releases the accelerator 3| the engine shaft 43 quickly comes to its idling speed while the momentum of the car prevents 253 the shaft 45 from correspondingly reducing its rate of rotation. It may be thatY the operator will wish to increase the speed of the car before the rate of rotation of the two shaftshas become synchronized. In his effort to increase the speed 30J of the car he again depressesk the pedal 3| which opens the throttle and vents the power cylinder through opening 81 as has been explained. This. action would be attended by a prompt reengagement of the clutch. If such reengagement oc- 35'l curs while the shaft 45 is rotating faster than shaft 43, the engine momentarily checks the car speedv by acting as a brake, an operation which the operator does not wish. This invention provides means to prevent the clutch reengagement under 40a Y such circumstances until the shaft 43 under the influence of the opening throttle attains the speed, ofV shaft 45. A iiexible shaft |0| within a flexible shaft housing |03 takes its drive from a gear- |05 in the gear housing 29. This gear |05 is ro- 455. tated by one of the gears of the constant mesh; train. Itis therefore driven in timed relation toI shaft 45. Another flexible shaft |01 is drivenby,l gearing |09 associated with the crankshaft 43.` A double pump has pump or blowerfmecha- 50i nism ||3 driven by fiexible shaft |01 atfone end,'. andrpump or blower mechanism ||5 driven byy shaft V| 0| at the other end. Air is drawn in from; the atmosphere by pump ||5 into thespace between the two pumps and discharged bypump I3 55; at the other end of the double pump element; From the space between the pumps a pipe ||1 connects with the interior of a bellowsI ||9, seecured at one end to the bottom of a cup |2 The:` other end of the bellows is connectedto the bot- 60# tom of a telescoping cup |23. A rod |25 con nects the bottom of cup |23 by a pivot to a piston: |21 slidable in the control member 85. 'I'he :pis-- ton may ,slide to open or close the opening 81.

A spring |29 is seated against the 651 end of the control member 85 and also engages the bottom of cup |23. 'I'his spring operates to.- Y bias the cup |23 to a position corresponding toI a location of piston |21 removed from the vent 81. This mechanism has no inuence upon the operation of the clutch release mechanismexcept as follows.

If the shaft 45 is rotating faster than shaft 43 so that the engagement of the clutch would tend to render the engine active as a brake, pump H5 75 is delivering air to the space between the pumps is operable through pipe ||1 and the bellows H9 to push the piston |21 over the vent 81, so that the air cannot escape from the power unit and permit the clutch to come into engagement. When the shaft 45 slows down or when the opening throttle increases the rate of rotation of shaft 43 so that the two shafts rotate at the same speed, the internal pressure between the pumps is relieved and the piston |21 withdraws from opening 81 influenced in doing so by spring |29. Clutch engagement then-occurs. With this arrangement the vehicle coasts when the accelerator is released since the clutch is also released by the action of the power unit. When the accelerator is again depressed, the clutch will not be immediately engaged. It will not engage until the rotation of shaft 43 is equal to that of shaft 45. The objectionable retardation referred to above is therefore avoided.

On Fig. 2 is shown a similar control employing a liquid pump control mechanism instead of a control effected by air pumps. In this gure the several parts are the same as in Fig. 1 with the exception of the pump control device. The flexible cable |03 from the clutch shaft operates a liquid gear pump 3|, and the cable |01 from the crankshaft operates a gear pump |33. The two pumps are located in a housing |35 having a passage |31 from the outlet of pump |3| to the inlet of pump |33. The passage |39 connects the outlet of pump |33 with the inlet to pump |3|. A cross passage |4|, between the passages |31 and |39, is controlled by a valve |43 biased by a spring |45 to close the passage and prevent a iiow from passage 31 to passage |39, except under pressures in 31 sufficiently high to overcome the valve spring. The pipe |1 opens out from the passage |31 and communicates with the bellows enclosed within parts |2| and |23 as before. A reservoir |41 communicates with passage |39 and keeps the chamber passages filled with liquid. With this arrangement the double pump mechanism does not interfere with the operation of the clutch release and engagement except when the clutch shaft rotates at a speed above that of the engine shaft. Under this condition pressure is built up in passage |31 and this pressure acting through uid within pipe ||1 moves the piston |21 and closes the outlet 81 as before, thus preventing the venting of the power unit 41 and the reengagement of the clutch.

Fig. 3 shows still another arrangement by which a single pump may do the work of the double pumps of Fig. l and Fig. 2. In this gure the crankshaft 43' is formed with a pump chamber within which is a rotating vane |53 formed as an extension on the end of clutch shaft 45. The bearing between the ends of the shafts is designated by numeral |55. An inlet tube |51 is used to receive oil from the engine lubricating system, and an outlet |59 is connected by a pipe |6| which leads (like pipe ||1 in Fig. 1) to the same control mechanism as is used in the forms of the invention shown by Figs. l and 2. With this third form of the invention, as long as no relative rotation occurs between the two shafts 43 and 45', no pumping action occurs. When, however, shaft 45 rotates faster than 43', fluid is pumped through outlet |59 and tube |6| to the same control mechanism as is illustrated in Fig. 1. nder the influence of such relative motion, the power cylinder is prevented from being vented to the atmosphere and the clutch is not able to` reengage. As soon as the two shafts assume the same rate of rotation the pumping ceases and the clutch is permitted to reengage.

I claim:

1. In a moto-r vehicle, an engine having an engine shaft, a driving shaft, a clutch to couple said engine shaft and said driving shaft, power means to release said clutch and means dependent upon a difference in rates of rotation of said shafts to prevent clutch engagement together with engine control means and manually operable means to render active said power means for releasing the clutch and to simultaneously and successively operate said engine control means.

2. In a motor Vehicle, an engine having an engine shaft, a driving shaft, a clutch to couple said engine shaft and said driving shaft, power means to release said clutch and means dependent upon a difference in rates of rotation of said shafts to prevent clutch engagement, said power means including a power cylinder and a movable valve to provide a connection between said cylinder and a source of suction in one position of the valve and with the atmosphere in a second position of said valve, and saidmeans to prevent clutch engagement comprising amovable member dependent upon a variation of the rates of rotation of said shafts to prevent the venting of said power cylinder to the air.

3. In a motor vehicle, in combination, an internal combustion engine, a clutch for said engine, a clutch shaft, a differential device for producing a motion of a part, the direction of this motion being in one direction when the speed of the clutch shaft exceeds the engine speed, and in the reverse direction when the engine speed exceeds the clutch shaft speed, a power device arranged to disengage the clutch by overcoming the clutch spring, a control for the power device, a connection between the differential device and the power device which prevents clutch reengagement when the clutch shaft speed exceeds the engine speed.

4. In a motor vehicle, in combination, an internal combustion engine, a clutch for said engine, a clutch shaft, a fluid pump driven by the clutch shaft, a second fluid pump driven by the engine, a connection between the outlet of the rst pump and the inlet of the second pump, a diaphragm acted upon by the pressure in the connection between the pumps, a power device arranged to disengage the clutch by overcoming the clutch spring, a control for the power device, a connection between the diaphragm and the control for the power device by which clutch reengagement is prevented when the clutch shaft speed exceeds the engine speed.

5. In a motor vehicle, in combination, an internal combustion engine having a crankshaft, a clutch for said engine, a clutch shaft, one element of a uid pump fixed to the crankshaft, a relatively movable element of the pump connected to the clutch shaft, means to supply uid to the pump, a device hydraulically connected to the pump which device has an element moving under fluid pressure, a power device arranged to disengage the clutch by overcoming the clutch spring, a control for the power device, a connection between the control and the power device said'fengine, a clutch shaft, aA differential device for producing a limited motion of a part, the direction of this motion being in one direction when -the engine speed exceeds the clutch shaft speed 'and in the reverse direction 'when the clutch shait speed exceeds the engine speed, a diarphragmi'orming a wall of a closed chamber, a connection between the closed chamber Vand a 'Valve casing, a connection between the valve casfl5 Aing and the intake manifold, a control valve in vthevalve casing arranged'to open or close the connection between the chamber and theintake manifold, 'a connection from the closed chamber to a second Valve casing, said second valve casing i having an openingto atmosphere, a valve in the 'second ca'sing'c'onnected to the moving part of vthe diierentialdevice whereby air is admitted to V'the'SeCOnd valve casing and the closed chamber when the engine'speed is equal to or greater than the clutch' vshaft speed, but is excluded when the clutch nshaft speed' is greaterfthan the engine fspe'e'd, Y l

7,." Ina motor vehclegan -"a driving Shaft, a clutch engine havinga shaft, to couple saidshafts,

30 yielding means to effect clutch engagement, power V*means to release said clutch, mechanism to render aosta `-"'s`a`idlpo" \'ver means operable "or inoperable, control 'e'ans for fs di riiehal ism-'and other `means-responsive to `ra "difference 'in' rates f rotation of id "shafts "and operable fupon s'ai'd mechanism, iiespective'f the action ofsa'id control'meansv 5 to prevent clutch-re'ngagement after release- A8. 'In' amotorvehicle, an engine having a shaft, jaflgwingjsnafa aeliitch tocoupie said shafts, aver 'r'ne'ans to 'releasesa'd clutch,l mechanism means operable or rinoper@` lo lable, eontr'ol 'means for said' mechanism'and other j' means `responsivev toa difference in'rates of rotation of 'said shafts Aand Topsrable upon said me'chanism, irrespective'of the action of`said control "means to` prevent clutch reeng'agement'afterre-v 15 ylease, said( other means comprising a-p1ur`alityfof pumpsj'o'ne driven'by ther engine shaftQthefother by the drivingr shaft, conduit means'between' said pumps and movable means controlled by pressnre in 'said conduit Vand voperable nponsaidgo4 mechanism.`

9. In a motor vehiclefainf-'eng'ine havingan engine shaft, a driving shaft, a clutch to couple said engineshaft and saidV driving shaft, yielding means to 'bias saidclutch to engaged posi-25 tion, powerV means to releasesaid clutch and rotatable means acutated by a.l difference iny rates offrotation of saidshafts to prevent clutch-"engage'ment. i f v f JOHN H. HUNT. so 

